Years ago, we used to read that the
body renews itself every seven years.
(This might make one wonder why we continue
to look the same or even older
when we actually have new atoms making up our frame.)
After decades of scientific investigation,
we are now told that cycle of renewal may be less than five years.

Present research suggests that fully
98 percent of the atoms in the human body
are replaced within a year's time
Certain tissues, such as bone and nerve, take longer to regenerate.
Their atoms require longer periods to be recycled.